Early Concepts of Glaciation

The glacial theory was developed in the early 1800s in the
mountains of western Europe. Jean de Charpentier and Jens
Esmark, as well as many other natural scientists, are credited
with initial discoveries and development of the concept that
glaciers had formerly expanded over larger areas. No single
person invented the idea (Cunningham 1990).

In Scandinavia, Jens Esmark concluded in 1824 that glaciers
had once been much larger and thicker, and had covered much of
Norway and the adjacent sea floor. He attributed erratic
boulders and moraines to glacial transportation and deposition.
He also recognized that glaciers were powerful agents of erosion
that had carved out the Norwegian fjords (Cunningham 1990).

In the early 1830s, Jean de Charpentier began to marshall
the scientific evidence for former alpine glaciation. He
observed moraines, striations, and erratics, as well as existing
glaciers of the Swiss Alps, and presented his conclusions in a
very persuasive manner (Teller 1983). His ideas initially met
with much skepticism, but his work eventually became quite
influential. During this time interval, scientists generally
held two contradictory views about how to explain the past
development of the Earth.

Catastrophism -- Earth had suffered a series of great
catastrophies, each of which completely reformed the surface
of the Earth and caused extinction of all life. Totally new
and fully developed forms of life appeared spontaneously
during the period of stability that followed each catastrophy.
The latest catastrophy was a great flood--the biblical deluge.

Uniformitarianism -- Earth's features were gradually formed
in a "uniform" manner by the same processes now in
operation: erosion, sedimentation, volcanism, etc. Life had
developed continuously by slow evolution. Cataclysms or
catastrophies had not taken place.

One of those, who at first disbelieved de Charpentier, was
Louis Agassiz, a famous Swiss zoologist. Through his own
observations, Agassiz came to accept the concept of former alpine
glaciation, and then carried the idea much further. In 1837 he
proposed that vast sheets of ice had once covered much of the
northern hemisphere. This was a radical suggestion, for at that
time the modern ice sheets in Greenland and Antarctica were
completely unknown. Agassiz was a highly energetic and
controversial naturalist, speaker, and writer. He travelled
widely and popularized the idea of a geologically recent ice age
as the latest catastrophy in Earth history.

Agassiz undertook detailed studies of glacier movement in
Switzerland in the 1840s, and he influenced James D. Forbes, a
Scotch physicist, to begin similar glaciological research in the
French Alps. Forbes established that glaciers move in part by
internal "viscous" (plastic) deformation, in contrast to the more
popular dilatation or regelation theories of the day (Cunningham
1990). Agassiz and Forbes were initially close friends, but they
became bitter enemies over questions of priority and integrity in
their glaciological discoveries.

By the mid-1800s, the glacial theory existed at three levels
of acceptance.

Alpine glaciers -- Modern glaciers in the Swiss Alps and
Norway had once extended farther down their valleys than
today = uniformitarian process, local events (Forbes).

Mountain ice caps -- Glacier cover in the Swiss Alps and
Norway had once been much thicker (or mountains higher) so
that ice caps formed and spread into adjacent regions =
extended uniformitarian process, regional events (Esmark and
de Charpentier).

Continental ice sheet -- Vast sheet of ice spread from the
Arctic and covered all of Europe as far south as the
Mediterranean (also in North America) = global catastrophy
and biological extinctions (Agassiz).

The glacial theory was initially opposed by a sizeable
number of natural scientists, who prefered to interpret landscape
features as the results of a great biblical flood. Some glacial
deposits in former marine areas do, in fact, contain fossil
shellfish. During the next few decades, those who opposed the
glacial theory were either converted or died. The effects of
glacial erosion and deposition were observed widely in Europe,
the British Isles, and in North America. By the end of the 19th
century, the glacial theory had been refined and was firmly
established.

Greenland Ice Sheet

During the 1800s, the Arctic region was the focus of intense
scientific and commercial exploration activity, as various groups
sought to find a "northwest passage" from Europe to Asia.
Greenland was part of this picture, and coastal portions of the
large island were visited by many expeditions. Access to the
interior was blocked by glaciers and snow. Several attempts to
penetrate inland using conventional techniques (horses and
wagons) failed miserably. Knowledge of Greenland was so
inadequate that some geographers thought the interior might be a
lush, warm oasis!

The first expedition to cross the Greenland Ice Sheet was
led by Fridtjof Nansen, a Norwegian, along with five companions.
They succeeded in 1888, where others had earlier
failed, by adapting winter travel techniques of the Lapps and
Eskimoes. They used skis and snowshoes and pulled light-weight
sleds with their equipment and supplies.
Nansen's expedition proved conclusively that Greenland is
covered by an ice sheet, and thereby confirmed Agassiz's daring
proposal made half a century earlier.
Another Norwegian explorer, Roald Amundsen, was the first person to
reach the South Pole in 1911.

By the end of the 19th century, real opposition to the glacial theory
was gone, and new evidence for multiple glaciations was beginning to
emerge. Both in Europe and in North America four or more glacial
periods separated by interglacial episodes were identified. So the
ice ages took on a cyclic character, which is still the subject of
much scientific research and debate. The global catastrophy of Agassiz
was discarded in favor of the regional approach first put forth by
Esmark and de Charpentier.